1. Field of the Invention
This invention relates to conveyor rollers used in glass tempering ovens, and more particularly concerns improved means for securing an end cap onto the conveyor roller.
2. Description of the Prior Art
Miller U.S. Pat. No. 3,867,748, which issued on Feb. 25, 1975 and which is incorporated herein by reference, discloses a conventional cylindrical ceramic conveyor roller for a glass tempering oven. FIG. 10 of U.S. Pat. No. 3,867,748 shows an end cap that is mounted onto a ceramic roller using an adhesive that is placed in cavities formed inside the end cap. A problem with this roller is that it tends to loosen from the end cap during use since the adhesive used to join the end cap to the ceramic roller begins to break down at about 600.degree. F., well below the temperature of about 1300.degree. F. that it is exposed to during use. As the adhesive breaks down in the end cap, the end cap starts to slip and starts to wear down the ceramic roller. Further, if the ceramic roller comes loose from the end cap, it may hit into and break other rollers in the oven. Also, as the roller becomes loose in the end cap, it begins to bounce, and by doing so it damages the glass rolling over it and leaves marks in the glass.
Another prior art roller attempted to solve the above problem of securing the end cap to the roller by drilling a pin into the side of the ceramic roller through the cylindrical end cap wall to secure the roller in place with respect to the end cap. However, this pin may cause fracturing of the roller.